1. Field of the Invention
The invention relates to a medical nuclear contrast medium, and more particularly to a nitroimidazole-amino acid hypoxia contrast medium, a precursor, preparation method, and use thereof.
2. Description of the Related Art
Tumors have become one of the major killers of human health. Malignant tumors usually need to be surgically removed, or be removed using chemotherapy or radiation. These therapies, however, have very negative effect on patients, since not only tumor cells will be killed, but also normal cells will be damaged to various degrees, which leads to mental affliction as well as decline in physical strength of the patients. Therefore, an early detection and diagnosis of tumors are very much desired, so that tumor cells can be eradicated at an early stage and the patients can obtain a new life. Scientists have already discovered that malignant tumors contain hypoxic cells and it is possible to detect tumor cells by testing cellular oxygen level. It has been reported that oxygen electrodes can be used to test cellular oxygen level. However, this method is very limited in terms of in vivo application. In recent years, nuclear technology has been applied in medical field for the detection of hypoxic tumor cells. Nuclear technology deploys hypoxia imaging technique which enables it to be detained in hypoxic cells, and then detects the oxygen level through imaging technology, which leads to the detection and diagnosis of malignant tumors. Nitroimidazole and their derivatives are used as radiation sensitizers. Their metabolisms inside cells are determined by the available cellular oxygen. Therefore, hypoxic cells can be imaged by labeling these compounds with radioactive nuclides. Nowadays, nuclear technology has become a focus of radiology medicine and hypoxia cellular imaging has also received a lot of attention. For example, 18FMISO, 99mmTc-HL91 and other compounds have been frequently used in clinic imaging research as hypoxia contrast medium. However, they possess a lot of drawbacks such as low absolute intake value by tumor cells, long imaging time and high cost, etc. As a result, a more effective tumor contrast medium is still in need.